Marcia Cleveland's Dover Solo: Swimming the English Channel. Since 1875, when Captain Matthew Webb became the first person successfully to swim the English Channel, more people have been in outer space than have duplicated his feat. On July 29, 1994, Marcia Cleveland became the 445th person to swim the English Channel. This is the story behind the swim: the process, the preparation, and the training. Discover what motivated Marcia to swim the 23-mile Strait of Dover where the summer water temperature averages only 60 degrees Fahrenheit.